Henri knab



H. KNAB.

MICROMETRIC TRACING GAGE.

APPLICATION FILED APR.21. 1917.

1 ,322,3 U22?, Pztenteggl, 1919.

IlIllIllllIllllllllIllllIlIIllIIlllIllIllllllIllllIIIlI|lllIll|llIlllllllllllllllllllllvl. IIP

Henri lli/gob Jnuenor UNITED sTATEs PATENT oEEicE.

HENRI KNAB, 0F PARIS, FRANCE.

MICROMETRIC TRACING-GAGE.

To all lwhom t may concern.'

Be it known that I, HENRI KNAB, citizen of the Republic of France, residing at 8 Rue du Chalet, Paris, in the Republic of France, have invented new and useful Improvements in Micrometric Tracing-Gages, of which the following is a specification.

The object of the present invention is a inicrometric tracing gage which consists. essentially of a slotted supporting tube mounted upon a base and containing a main screw operated by a milled vernier head; the main screw being thus adapted to rotate within the slotted base. This main screw engages with a threaded piece which forms part of a sliding piece movable upon the supporting tube and carrying the trac' ing point of the gage. A very simple'device allows of throwing the threaded piece mounted on the sliding piece, out of contact with the main screw, so that the sliding piece can slide freely upon its supporting tube; the apparatus is completed by suitable means for clamping the sliding piece upon the supporting tube and also by atracing point mounted: upon the sliding piece.

The accompanying drawing represent-s an example of a method of execution of a micrometrie tracing gage according to the present invention.

Figure l is a perspective view of the tracing gage;

Fig. 2 is a partial section along the axis, according to the line A-A of Fig. 1; t

Fig. 3 is a larger scale view of a section of the coupling and uncoupling device for the threaded piece of the sliding piece, and the main screw;

F igs., 4;, 5 and 6 are detail views in front elevation showing certain part-s of this device.

Referring to Figs. 1 and 2 it is observed that the tracing gage comprises essentially a steel tube a, which is slotted as shown at and screwed or otherwise mounted upon a cast iron or steel base t; in the interior of the tube rotates a main screw c which is held in place by the lock nuts d, the screw being operated by a milled head e provided with a Vernier graduation. The tube a acts as a support for a sliding piece f which carries the tracing point g of the gage, the point being clamped by the milled head h, while the sliding piece can be clamped upon the tube a by means of the milled head z'. The sliding piece carries a cylindrical socket Specification of Letters Patent.

Application filed April 21, 1917. Serial No. 163,632.

j which contains a cylindrical plug 7c, this latter being seen in front elevation in Fig. 4; Said plug carries at its end, as will be observed, a notched portion Z having two plane parallel sides, whose distance apart is somewhat less than the width of the slot Z2. The portion Z thus engages in the slot and is held in contact with the main screw by the spring m, whose other end bears upon the nut n screwed into the socket j. Upon the head of this screw are two inclined ways 0, separated by two depressions p, these being shown in section in Fig. 3 and in elevation in Fig. 5. Upon the milled head g (seen in elevation in Fig. 6) are two pro-k jections r adapted to work upon the inclined ways o or the depressions p of the nut n. This head is maintained in place by a screw s passing through it and which screws into the back part of thel plug 7c.

When the projections r yoi" the head g lie upon the depressions p of the nut n, the plug 7c comes in contact with them ain screw by means of the notched piece Z. By turningthis head counter clock-wise, the progections 7" mount upon the inclined ways o, and this draws back the plug so as to bring the threaded part Z out of contact with the main screw. In this way, the head g allows of coupling and uncoupling the portion Z.

The tracing gage is employed in the following way: The milled head t' being turned so as to release the sliding piece and the head g being in the uncoupling position, the slidin piece is displaced along the support` ing tu e a so as to bring the tracing point g approximately to its working position. The point is suitably adjusted in its holder u, then it is clamped by the milled head 7i, after which the operating head e is rotated, and this allows of displacing the sliding piece f and with it the point g, within one-twentieth of a millimeter. l Then the head z' is turned to clamp the slide. To draw other lines parallel to the first, the slide is unclamped by the head z', and the distance between the lines is shown by the operating head e.

The advantage of the present tracing gage is that it allows of a rapid tracing of several lines in succession and at very exacty distances, without needing the use of a graduated scale, and again, the point always remains horizontal and the line is sharp and clear.

The tracing gage above described is shown as an example of the present invention, and it is understood that it can be modified in its shapes, materials, dimensions and details without in any way departing from the principles of the present invention.

Having now described my invention, what I claim as-new and desire to secure by Letters Patent is:

l. A micrometric tracing gage comprising in combination: a base, a slotted tube mounted upon said base, a main screw rotating withinsaid slotted tube, ahead which rotates said main screw, a sliding piece Inovable along said slotted tube and provided with inclined surfaces, a tracing point, means for clamping the tracing point in said slidingpiece, a plug adapted to ylongitudinally slide in the sliding piece in a direction transverse tothe length of said main screw and having a notchedpart which is adapted to engage with the main screw, a spring acting to press the notched part of the plug into engagement with thc main screw, a rotating member having surfaces adapted to ride upon rotation upon t-he inclined surfaces on the sliding piece and disengage the notched part from the main screw and means for holding the rotating member and the plug against relative displacement, substantially as described and lfor-the purpose set forth. v

- 2. A micrometric tracing gage containing in combination: a base; a slotted tube mounted upon said base; a main screw rotating within said slotted tube; a head which rotates said main screw; a sliding piece movable onsaid slotted tube; a holder mounted on Vthe sliding piece; a tracing point movable within saidholder; a set screw for clamping the tracing point in said holder; a cylindrical soclie'ton said sliding piece; a cylindrical plug movable within said cylindrical socket and provided with a notched part engaging in the slot of the aforementioned tube and adapted to enter in contact with the main screw; a nut screwed at the end of said cylindrical socket and having a head provided withtwo rising inclined ways and two depressions; a spring placed between the cylindrical plug and said nut and yadapted to press the notched part into engagement with the main screw; a'milled head provided with two projections of less width'than that ofthe depressions on said screw and adapted, upon rotation, to disengage the notched part from the main screw; a screw which is threaded into said cylindrical plug so that its head shall retain said milled head; substantially as described and for the purpose set forth.

In testimony whereof AI have signed my name'to this specification in the presence of two subscribing witnesses.

HENRI KNAB.

IVitnesses Louis Mosns, CHAs. P. PRnssLY. 

